DSYTRS_AA_2STAGE solves a system of linear equations A*X = B with a real


 symmetric matrix A using the factorization A = U*T*U**T or


 A = L*T*L**T computed by DSYTRF_AA_2STAGE.

UPLO

          UPLO is CHARACTER*1


          Specifies whether the details of the factorization are stored


          as an upper or lower triangular matrix.


          = 'U':  Upper triangular, form is A = U*T*U**T;


          = 'L':  Lower triangular, form is A = L*T*L**T.

N

          N is INTEGER


          The order of the matrix A.  N >= 0.

NRHS

          NRHS is INTEGER


          The number of right hand sides, i.e., the number of columns


          of the matrix B.  NRHS >= 0.

A

          A is DOUBLE PRECISION array, dimension (LDA,N)


          Details of factors computed by DSYTRF_AA_2STAGE.

LDA

          LDA is INTEGER


          The leading dimension of the array A.  LDA >= max(1,N).

TB

          TB is DOUBLE PRECISION array, dimension (LTB)


          Details of factors computed by DSYTRF_AA_2STAGE.

LTB

          The size of the array TB. LTB >= 4*N.

IPIV

          IPIV is INTEGER array, dimension (N)


          Details of the interchanges as computed by


          DSYTRF_AA_2STAGE.

IPIV2

          IPIV2 is INTEGER array, dimension (N)


          Details of the interchanges as computed by


          DSYTRF_AA_2STAGE.

B

          B is DOUBLE PRECISION array, dimension (LDB,NRHS)


          On entry, the right hand side matrix B.


          On exit, the solution matrix X.

LDB

          LDB is INTEGER


          The leading dimension of the array B.  LDB >= max(1,N).

INFO

          INFO is INTEGER


          = 0:  successful exit


          < 0:  if INFO = -i, the i-th argument had an illegal value

Univ. of Tennessee

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NAG Ltd.

November 2017